PROBLEM TO BE SOLVED: To provide technique which reduces resistance rise of an upper electrode, damage on a membrane and degrading in insulation resistance between the upper electrode and a lower electrode even if level difference occurs by dividing the lower electrode into each element.SOLUTION: A ultrasonic transducer comprises: a plurality of lower electrodes 203 an insulating film 204 covering the lower electrode a plurality of cavity parts 205 formed to overlap with the lower electrode 203 on the insulating film 204 an insulating film 3401 filling a clearance of the cavity parts 205 an insulating film 206 covering the cavity part 205 and the insulating film 3401 a plurality of upper electrodes 207 formed to overlap with the cavity part 205 on the insulating film 206 and a plurality of wirings 208 connecting them. Surfaces of the cavity part 205 and the insulating film 3401 are flattened at the same height.COPYRIGHT: (C)2013,JPO&INPIT【課題】下部電極を各素子に分割することで段差が生じても、上部電極の抵抗上昇、メンブレンへのダメージおよび上部電極と下部電極間の絶縁耐性低下を低減する技術を提供する。【解決手段】複数の下部電極203と、下部電極を覆う絶縁膜204と、絶縁膜204上に下部電極203と重なるように形成された複数の空洞部205と、空洞部205の間を埋める絶縁膜3401と、空洞部205および絶縁膜3401を覆う絶縁膜206と、絶縁膜206上に空洞部205と重なるように形成された複数の上部電極207とそれらを結ぶ複数の配線208を備えた超音波トランスデューサにおいて、空洞部205と絶縁膜3401の表面が同じ高さに平坦化されている。【選択図】図34
